SUNDAY, June 15 (HealthDay News) -- The current standard screening test for prediabetes in children often fails to detect the condition, Canadian researchers contend.

Ironically, the findings are from a study group of 172 obese children -- ages 5 to 17 -- who joined a program to help them slim down to a healthy weight.

The standard diabetes test for children is the fasting plasma (blood) glucose test, but it identified almost three times fewer children with diabetes than the glucose stress test, also called the oral glucose tolerance test. The glucose stress test takes longer, because blood is taken from the patient after fasting and again two hours after drinking a sugary solution.

Using the fasting blood glucose test, the researchers found that only 8 percent of the children in the study met the diagnostic criteria for prediabetes. But the glucose stress test indicated that 25 percent of the children had prediabetes.

"A large proportion of the children with prediabetes would not have had their condition recognized," lead author Dr. Katherine Morrison, of the pediatrics department at McMaster University in Hamilton, Ontario, Canada, said in a prepared statement.

The researchers also found the fasting blood glucose test identified metabolic syndrome in only 5.2 percent of the children, while the glucose stress test detected metabolic syndrome in 12.8 percent of the children. Metabolic syndrome is a cluster of risk factors (including high blood sugar) for diabetes and heart disease.

The findings were expected to be presented over the weekend at the Endocrine Society's annual meeting in San Francisco.

"Prediabetes and metabolic syndrome are common in obese children but are not readily identified with the currently recommended test. They require a glucose stress test," Morrison said.

Prediabetes and metabolic syndrome often cause no obvious symptoms, she added. Early detection is important, because changes in diet, regular exercise and moderate weight loss can help prevent or delay diabetes and metabolic syndrome.